The need for and use of jacketed small arms ammunition projectiles is well known. T. F. Werme in U.S. Pat. No. 2,336,143 discusses the conventional method of making jacketed projectiles in the 1941-1943 period which utilized a multiplicity of operations comprising first alternate drawings and annealings of a gilding metal jacket disc until it is formed in the shape of an elongated cup and then subsequently inserting a separately formed slug into the prepared jacket. In addition to the multi-operations and expensive equipment needed to make jacketed projectiles under this process, the end product had certain undesirable deficiencies such as variation in the jacket thickness and concentricity. This was the conventional method of making jacketed projectiles until the late 1960's when J. Darigo, et al. disclosed in U.S. Pat. Nos. 3,349,711 and 3,431,612 a method of making a small arms jacketed projectile by electrodepositing a deformable metal jacket over a softer deformable projectile core and then forming the plated projectile to its final dimensions.
As disclosed in the Darigo patents, lead cores are tumbled and deburred, cleaned, rinsed, pickled, rinsed and then given a copper strike in a plating bath for a predetermined period of time until the lead cores are entirely covered with a thin coating of copper. This copper strike plating bath, which is generally an alkaline cyanide containing formulation, is neccessary to prevent the main plating bath from becoming contaminated with lead. The main plating bath, which is strongly acidic, would dissolve lead and produce copper jackets that tended to be brittle.
The thinly copper coated cores are then electroplated in the main bath until the necessary thickness of copper has been deposited thereon. The resulting jacketed projectiles are then rinsed, pickled, rinsed, a corrosion inhibitor added and then dried. The plated projectiles are then fed to final forming dies where they are formed to the desired configuration and dimensions required.
More than 25 years since its' introduction, the above-described electroplating method is still widely used in the production of jacketed small arms projectiles, even though manufacturers have had to cope with numerous processing steps, the danger of cyanide in the strike bath and the added cost for its' waste treatment and disposal. In addition, long plating times are required in the main electroplating bath to deposit the thickness required for the jacketed small arms projectiles. The present invention is directed to providing a new process to produce jacketed small arms projectiles which decreases the number of process steps, eliminates the use of cyanide and its associated disadvantages, and significantly reduces the overall processing time while providing jacketed small arms projectiles that exhibit improved lubricity characteristics. This characteristic can greatly improve the ability of the part to be further formed or deformed which is an important step in the manufacture and subsequent final use of the jacketed small arms projectiles as firearms ammunition.